This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We are using native mass spectrometry to determine how many karyopherins can bind to a single isolated FG-nucleoporin and conversely how many FG-nucleoporins can bind to a single karopherin for a number of different FG-Nup/Karyopherin combinations